1. Field of the Invention
The present invention relates to heat sink assemblies used to dissipate heat from electronic devices, and more particularly to a heat sink assembly having a spring clamp for securely retaining a clip in a heat sink of the assembly.
2. Related Art
Advancements in microelectronics technology has resulted in electronic devices such as central processing units (CPU) that are able to process signals at unprecedented high speeds. During operation of such electronic devices, large amounts of heat are produced. The heat must be efficiently removed, to prevent the electronic device from becoming unstable or damaged. A heat sink assembly is commonly used to dissipate heat from the electronic device.
A typical heat sink assembly comprises a heat sink and a clip. The clip is used to fasten the heat sink onto an electronic device. An example of a conventional heat sink assembly is disclosed in U.S. Pat. No. 5,464,054. In this assembly, a wire clip fastens a heat sink onto an electronic device. The wire clip comprises a central portion and two fastening portions respectively extending from opposite ends of the central portion. The heat sink comprises a base, and a plurality of pin fins extending upwardly from the base. A longitudinal slot is defined in the base for receiving the central portion of the clip. A plurality of barbs is formed on the base along the slot. The central portion of the wire clip is retained in the slot by the barbs. A hook is formed at a free end of each fastening portion, for engaging in a corresponding hole of a motherboard. The hooks thereby resiliently secure the heat sink to the electronic device. However, it is laborious to manipulate the central portion of the wire clip so that it is retained in the slot of the heat sink by the barbs. In addition, when the assembly is subjected to vibration or shock during use, the clip is prone to rotate in a plane that is parallel to the base, and is prone to be displaced in directions that are parallel to the slot. This can adversely affect thermal engagement of the heat sink with the electronic device.
Another example of a conventional heat dissipating assembly is disclosed in U.S. Pat. No. 5,386,338. The assembly comprises a wire clip for attaching a heat sink to an electronic device. A spring clamp is also required. The clamp has a semicircular bottom for receiving a central portion of the clip, and two spring lugs extending from opposite sides of the semicircular bottom. The clamp fastens the wire clip onto the base of the heat sink via the lugs. However, the wire clip is prone to rotation and displacement, in much the same way as the wire clip of the heat sink assembly described in the above paragraph.
In view of the above, an improved heat sink assembly with a spring clamp which overcomes the above-mentioned problems is strongly desired.
Accordingly, an object of the present invention is to provide a heat sink assembly having a spring clamp which facilitates assembly thereof, the spring clamp having a simple structure.
Another object of the present invention is to provide a heat sink assembly including a heat sink and a wire clip attached to the heat sink with a spring clamp, whereby the heat sink assembly has a simple structure and is easily assembled.
To achieve the above-mentioned objects, a heat sink assembly of the present invention is used to attach a heat sink onto a heat-generating electronic device mounted on a motherboard. The heat sink assembly comprises the heat sink, a clip and the spring clamp. The heat sink has a base, and a plurality of heat dissipating pin fins extending upwardly from the base. A plurality of slots is defined between respective adjacent rows of the pins, in perpendicular crisscross fashion. The clip is made from a flexible metal wire. The clip comprises a central body with a raised portion in a middle thereof, and two arms respectively extending perpendicularly but in different directions from opposite ends of the central body. A hook is formed at a free end of each arm. The spring clamp comprises an elongate central pressing portion. A longitudinal opening is defined in the pressing portion, engagingly receiving the raised portion of the clip therein. Two pairs of elastically deformable wings extend from respective opposite sides of the pressing portion. The clamp is resiliently retained in corresponding slots of the heat sink, and thus secures the clip to the heat sink.